Apparatus for electric heating



1941- F. s. DENNEEN ETAL 2,266,176

APPARATUS FOR ELECTRIC HEATING Original Filed March 29, 1954 Fig. 5 g 2 WILLIAM 0.0mm FRANCIS S.DENNEEN and BY COURTNEY N. MITCHELL Patented Dec. 16, 1941 UNITED, STATES PATENT,

OFFICE.

APPARATUS FOR ELECTRIC HEATING Francis S. Denneen, Cleveland, William C. Dunn, Shaker Heights, and Courtney N. Mitchell, Strongsville, Ohio, assignors to The Ohio Crankshaft Company, Cleveland, Ohio, a corporation of Ohio Original application March 29, 1934, Serial No.

Divided and this application December 31, 1938, Serial No. 248,712

4 Claims.

tively heating articles of various kinds.

The invention is generally directed to a segmental block which may be easily opened to be placed in embraced relation with an article such as a shaft by which the same is inductively heated as desired and may thereafter be quenched to secure a desired metallurgical structure.

In supplying quench water from such a block to a heated article it is necessary to supply large quantities and at the same time provide means of escape for the spent fluid and steam resulting therefrom.

The general object of our invention therefore has been to provide quench conducting passages in the form of grooves'on the work adjacent face of the inductor to provide an outlet for the spent water and steam without the necessity for the same contacting the work. We thus eliminate the formation of surface bubbles on the heated work, which partially retards cooling underneath the bubbles and results in a spotty structure.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims; the annexed drawing and the following description setting forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various mechanical means in which the principle of the invention may be used.

In said annexed drawing:

Fig. 1 is an end elevation of our improved inductor showing a sectioned shaft therein;

Fig. 2 is a section through Fig. 1, as indicated by the lines 22 thereon; and

Fig. 3 is a plan view looking upwardly of the interior of the inductor block.

Referring now to the drawing, we provide a segmentally formed inductor block, indicated generally at 5, and comprising segments 1, 8 and 9, which cooperate to form an encircling ring lying about the bearing of the shaft. Leads I0 and H are integrally formed with the inductor portions 1 and 8 to supply periodically varying current thereto. This current may be of any desired frequency and strength and from any desired source and it is the flux field established in the surface zone of the adjacent bearing by reason of the proximity of the inductor which elevates said surface zone to the desired hardening temperature,

Supporting brackets I4, 15 and I6 carry the inductor segments to which they are suitably bolted, as by screws H. An insulated bushing is provided to insulate the bolts from metallic contact with th supporting segments through which they pass, and against which they bear.

The supporting members are hollow as hereafter described to supply adequate amounts of cooling water to the heated surface zone. Interposed between the segments and the adjacent portions of the inductor supported thereby are gaskets 20, which serve to electrically insulate the segments from the inductor portions and to seal the chamber formed between the parts against leakage.

The segment l6 and that portion of the inductor supported thereby may be separated from the other two segments and the remainder of the inductor block to permit enclosing the same about the shaft to be hardened. As the inductor portions are reassembled it is essential that good electrical contact be secured between the inductors and thus there are provided flanges 22 and 23 which flare outwardly from the abutting por tions I and 8 and lie in face to face relation with similarly extended portions 24 and 25 of the inductor section 9. Curved self-aligning contact blocks 28 are interposed between the extensions 23 and 24 and 22 and 25 respectively, to complete efficient electrical contact between the parts. The extensions are preferably of resilient construction to increase the effective contact between the surfaces.

The zone heated is quenched rapidly after attaining the desired temperature. As the rate of cooling of the surface is of great importance in obtaining hardness, provision is made for an ample supply of quenching fluid in order to almost instantly absorb the heat contained in the heated zone.

The quenching water by which the heated zone is cooled is supplied to the hollow chamber indicated at 32, formed between the inductor and its supporting segments. A pipe 34 connects through a valve 35 with a threaded connection leading into the aforesaid chamber. This valve is timed to open and deliver water to the heated surface in timed sequence to the end of the heating operation. Flexible connections 31 extend between the various supporting segments l4, l5 and IE to form a continuous quench supply between the various quench chambers.

A series of orifices 38 are provided in the work adjacent faces of the inductor segments and communicate with the interior of respective chambers to provide outlets by which quench may be forcibly sprayed against the work. As quench water is supplied to the chamber under pressure it passes through the orifices and discharges against the heated zone lying beyond the orifices. The volume is sufficient to very rapidly accomplish the cooling action and give the desired structure.

This quench, usually water, must not only be forcibly distributed in a large volume over the heated surface, but ample provision should be made to dispose of steam or other vapor formed at the time of quenching. .Unless this is accomplished insulating bubbles will form'on the heated surface and partially retard the cooling of the surface area so covered and thus result in a spotty structure. The surface may be kept clean by insuring complete condensation of the steam and by providing avenues for its escape so that it will not interfere with the flow and contact of the quenching liquid to and with all points on the surface. In order to accomplish this, recesses 39 in the work adjacent faces of the inductor and communicating with the quench orifices are provided and materially aid in the distribution of quench rapidly to all parts of the heated zone. As best shown in Fig. 2 it will be seen that the inductor in cross-section is convex at each end and concave in the central portion. The ends of the inductor flare away from the work as shown. By employing these grooves or recesses it is possible to provide sufficient space between the inductor and the work to accommodate an adequate supply of quenching fluid and at the same time maintain the portions of the inductor close enough to the work to attain the most efficient heating effect therefrom.

To provide discharge vents from the zone of the material, the inductor segments and the supporting segments are drilled, as indicated at 30, and an insulating sleeve is inserted in the drilled hole.

An air blow-off is employed to blow air through the quench chamber and orifices at the end of the quenching operation to clean out the orifices and expel the remaining moisture and to prevent the leakage of any remaining quenching fluid onto the succeeding bearing undergoing hardening. This air is supplied through a pipe 40 communicating with the three-way valve 35 already described and, by setting the valve properly, may be applied at will to the parts of the apparatus.

From the foregoing description it will be apparent that we have invented a novel inductor block by which improved heating and quenching of the surface zone to be hardened is secured.

invention may be employed instead of the one explained, change being made as regards the structure herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

We therefore particularly point out and distinctly claim as our invention:

1. An inductor comprising three members adapted to encircle an article to be heated, three inductor segments, one for each member, lying along the inner surface thereof and completely insulated therefrom, the adjacent surfaces of each member and its cooperating segment presenting a chamber, each chamber having means for communicating with a source of quenching fluid, each segment having the article adjacent surface thereof recessed, conduits communicating between each recess and a chamber, the ends of each recess being adapted for discharging spent quenching fluid, and means for circulating an alternating current through said segments.

2. A device for electrically heating an article, said device comprising a plurality of members adapted to encircle said article, a current conducting segment associated with and insulated from the article adjacent surface of each memher, the adjacent surfaces of each segment and its associated member presenting a chamber, the article adjacent surface of each segment presenting axial recesses each in communication with a chamber, the axial ends of each-recess being open, means for passing an alternating current through said segments and means for supplying a quenching fluid to each chamber whereby the spent fluid may be expelled through said ends.

3. The combination of an element adapted to lie in heating relation with an article to be heated, the article adjacent surface of said element being from one end thereof to the other convex, then concave and then convex, said surface having recesses therein extending from one of said ends to the other, means for supplying a quenching fluid to the inner portion of each of said recesses whereby the spent quench may escape through said recesses at said ends.

4. The combination of outer elements adapted for encircling an article to be heated, inner elements, one carried by each of said outer elements and electrically insulated therefrom, a chamber between each of said outer elements and their respective associate inner elements, conduits communicating between said chamber and the article adjacent surface of said inner element, means for supplying a quenching fluid to each chamber, said inner elements presenting curved outwardly extending surfaces, curved selfaligned contact blocks interposed between said curved surfaces whereby said inner elements and blocks are electrically connected and aligned, and means for supplying an alternating current to said inner elements.

- FRANCIS S. DENNEEN.

WILLIAM C. DUNN. COURTNEY N. MITCHELL. 

